Efavirenz or Atazanavir/Ritonavir Given With Emtricitabine/Tenofovir Disoproxil Fumarate or Abacavir/Lamivudine in HIV Infected Treatment-Naive Adults

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Currently, the preferred anti-HIV regimens used in the United States consist of two nucleoside reverse transcriptase inhibitors (NRTIs) and the nonnucleoside reverse transcriptase inhibitor (NNRTI) efavirenz (EFV). However, with new anti-HIV drugs being approved, alternative regimens need to be tested to determine if new drug combinations have increased effectiveness in treating HIV. The purpose of this study is to test the safety, tolerability, and effectiveness of four different regimens in HIV-infected adults who have never taken anti-HIV drugs.

Antiretroviral (ARV) treatment regimens consisting of EFV and two NRTIs are the most commonly prescribed regimens for the initial therapy of HIV-infected people in the United States. Such regimens are popular because the drugs are easy to administer, have overall excellent efficacy, and are well tolerated. However, because of concerns about long-term drug toxicity, the development of drug resistance, and potential complications in pregnant women, it is imperative that other drug combinations be investigated as possible alternative initial regimens. Drugs recently approved by the Food and Drug Administration (FDA) for HIV treatment include the protease inhibitor (PI) atazanavir (ATV) and the two NRTI coformulations emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) and abacavir/lamivudine (ABC/3TC). Data are limited on the efficacy of these new drugs when part of anti-HIV drug regimens. This study will evaluate and compare the safety, tolerability, and efficacy of four different treatment regimens in HIV-infected treatment-naive adults.

The treatment portion of this study will last 96 weeks after the last participant is enrolled. Participants will be randomly assigned to one of four arms:

NOTE: Lopinavir/ritonavir may be used in substitution of other drugs for certain participants.

Study visits will occur at study entry; Weeks 1, 2, 4, 8, 16, and 24; and every 12 weeks thereafter. A physical exam, blood collection, and urine collection will occur at most visits. Two pharmacokinetic blood samples will be collected from participants between Weeks 4 and 24. Participants will undergo adherence training at study entry and will be asked to complete adherence questionnaires at selected study visits. Some participants will be asked to participate in ACTG A5224s, a metabolic substudy of ACTG A5202.

The Data Safety Monitoring Board (DSMB) for A5202 met in January 2008 to review the study. After reviewing the study information, the DSMB noted that certain study regimens were significantly less effective than others. Specifically, ABC/3TC-containing regimens were not as effective in controlling the virus as TDF/FTC-containing regimens for participants entering the study with high viral loads. The DSMB also commented that participants assigned to ABC/3TC had a shorter time until they experienced side effects than participants assigned to TDF/FTC. The DSMB had no safety concerns for the other drug comparisons.

Based on DSMB review, in Feb 2008 participants who started the study with high viral loads were told whether they were taking ABC/3TC or TDF/FTC and offered the option to continue or change their NRTI study drug component, after discussion with their doctor. For participants who started the study with lower screening viral loads, study treatment continued without change.

For 74 participant the reason for first treatment modification was "unblinded and switched" as a consequence of the DSMB results (33 on EFV, ABC/3TC, and placebo FTC/TDF arm; 1 on RTV-boosted ATV, FTC/TDF, and placebo ABC/3TC arm; and 40 on RTV-boosted ATV, ABC/3TC, and placebo FTC/TDF arm).

A Phase IIIB, Randomized Trial of Open-Label Efavirenz or Atazanavir With Ritonavir in Combination With Double-Blind Comparison of Emtricitabine/Tenofovir or Abacavir/Lamivudine in Antiretroviral-Naive Subjects

Time From Randomization to Virologic Failure [ Time Frame: Follow-up time was variable,median follow-up was 138 weeks; see 'Amount of study follow-up' outcome for details ]

Blood samples for determining virologic failure were obtained at visit weeks 16 and 24 , and every 12 weeks thereafter. Virologic failure was defined as a confirmed plasma HIV-1 RNA level >= 1000 copies/mL at or after 16 weeks after randomization and before 24 weeks, or >=200 copies/mL at or after 24 weeks. The 5th percentile for time to virologic failure is the time (in weeks) at which 5% of the participants have experienced virologic failure.

Time From Treatment Dispensation to a Grade 3/4 Safety Event [ Time Frame: All follow-up while on initially assigned regimen; the median (25th, 75th percentile) follow-up while on initial regimen was 120 (54, 156) weeks and the range was 0 to 205 weeks. ]

Grade 3/4 safety event is defined as a grade 3 or 4 sign, symptom, or laboratory abnormality that is at least one grade higher than at baseline, total bilirubin and creatine kinase (CPK) were excluded. Grading used the Division of AIDS (DAIDS) 2004 Severity of Adverse Events Tables.

Time From Treatment Dispensation to Treatment Modification [ Time Frame: Follow-up time was variable,median follow-up was 138 weeks; see 'Amount of study follow-up' outcome for details ]

Treatment modification is defined as the 1st modification of the regimen, including a permanent discontinuation, switch, or substitution.

Secondary Outcome Measures
:

Time From Treatment Dispensation to Regimen Failure (First Occurrence of Virologic Failure or Treatment Modification) [ Time Frame: Follow-up time was variable,median follow-up was 138 weeks; see 'Amount of study follow-up' outcome for details ]

Blood samples for determining virologic failure were obtained at 16 and 24 weeks, and every 12 weeks thereafter. Virologic failure was defined as a confirmed plasma HIV-1 RNA level >= 1000 copies/mL at or after 16 weeks and before 24 weeks or >=200 copies/mL at or after 24 weeks. Treatment modification was defined as the 1st modification of the regimen, including a permanent discontinuation, switch, or substitution.

The Number of Participants With HIV-1 RNA Levels Less Than 50 Copies/mL [ Time Frame: At Weeks 48 and 96 ]

Number of Participants With HIV-1 RNA Levels Less Than 200 Copies/mL [ Time Frame: At Weeks 48 and 96 ]

Change in CD4 Count (Cells/mm3) From Baseline [ Time Frame: At Weeks 48 and 96 ]

Change was calculated as the CD4 count at Week 48 (or at Week 96) minus the baseline CD4 count (mean of pre-entry and entry values).

Number of Participants With Virologic Failure and Emergence of Major Resistance [ Time Frame: Follow-up time was variable,median follow-up was 138 weeks; see 'Amount of study follow-up' outcome for details ]

Emergence of resistant virus was assessed by genotypic testing performed at Stanford University for all participants who met criteria for virologic failure and retrospectively on baseline samples from these participants. Major mutations were defined by International AIDS Society-United States of America (2008), as well as T69D, L74I, G190C/E/Q/T/V for reverse transcriptase and L24I, F53L, I54V/A/T/S, G73C/S/T/A, N88D for protease.

Participants were to be followed for 96 weeks after the last enrollment. Accrual was expected to take 96 weeks, thus the planned follow-up time was 96 to 192 weeks, dependent on when in the study the participant enrolled. This outcome summarizes that total amount of actual follow-up in weeks from randomization to last contact.

Number of Participants With Virologic Failure [ Time Frame: Follow-up time was variable, median follow-up was 138 weeks; see 'Amount of study follow-up' outcome for details ]

Blood samples for determining virologic failure were obtained at 16 and 24 weeks, and every 12 weeks thereafter. Virologic failure was defined as a confirmed plasma HIV-1 RNA level >= 1000 copies/mL at or after 16 weeks and before 24 weeks or >=200 copies/mL at or after 24 weeks.

Cumulative Probability of Not Experiencing Virologic Failure [ Time Frame: At week 48 and 96 ]

Kaplan-Meier estimate of the cumulative survival probability at week 48 and 96. Blood samples for determining virologic failure were obtained at 16 and 24 weeks, and every 12 weeks thereafter. Virologic failure was defined as a confirmed plasma HIV-1 RNA level >= 1000 copies/mL at or after 16 weeks and before 24 weeks or >=200 copies/mL at or after 24 weeks.

Number of Participants With a Grade 3/4 Safety Event [ Time Frame: Over all study follow-up while on initially assigned treatment, median follow-up was 120 weeks ]

Grade 3/4 safety event is defined as a grade 3 or 4 sign, symptom, or laboratory abnormality that is at least one grade higher than at baseline, total bilirubin and creatine kinase (CPK) were excluded. Grading used the Division of AIDS (DAIDS) 2004 Severity of Adverse Events Tables. As-treated analysis censored at 1st modification of initially assigned regimen, participants who never started treatment were excluded.

Cumulative Probability of Not Experiencing a Grade 3/4 Safety Event [ Time Frame: At week 48 and 96 ]

Kaplan-Meier estimate of the cumulative survival probability at week 48 and 96. Grade 3/4 safety event is defined as a grade 3 or 4 sign, symptom, or laboratory abnormality that is at least one grade higher than at baseline, total bilirubin and creatine kinase (CPK) were excluded. Grading used the Division of AIDS (DAIDS) 2004 Severity of Adverse Events Tables. As-treated analysis censored at 1st modification of initially assigned regimen, participants who never started treatment were excluded.

Number of Participants With Treatment Modification [ Time Frame: Follow-up time was variable, median follow-up was 138 weeks; see 'Amount of study follow-up' outcome for details ]

Treatment modification is defined as the 1st modification of the regimen, including a permanent discontinuation, switch, or substitution.

Cumulative Probability of Not Experiencing Treatment Modification [ Time Frame: At week 48 and 96 ]

Kaplan-Meier estimate of the cumulative survival probability at week 48 and 96. Treatment modification is defined as the 1st modification of the regimen, including a permanent discontinuation, switch, or substitution.

Number of Participants With Regimen Failure [ Time Frame: Follow-up time was variable, median follow-up was 138 weeks; see 'Amount of study follow-up' outcome for details ]

Blood samples for determining virologic failure were obtained at 16 and 24 weeks, and every 12 weeks thereafter. Virologic failure was defined as a confirmed plasma HIV-1 RNA level >= 1000 copies/mL at or after 16 weeks and before 24 weeks or >=200 copies/mL at or after 24 weeks. Treatment modification was defined as the 1st modification of the regimen, including a permanent discontinuation, switch, or substitution.

Cumulative Probability of Not Experiencing Regimen Failure [ Time Frame: At week 48 and 96 ]

Kaplan-Meier estimate of the cumulative survival probability at week 48 and 96. Blood samples for determining virologic failure were obtained at 16 and 24 weeks, and every 12 weeks thereafter. Virologic failure was defined as a confirmed plasma HIV-1 RNA level >= 1000 copies/mL at or after 16 weeks and before 24 weeks or >=200 copies/mL at or after 24 weeks. Treatment modification was defined as the 1st modification of the regimen, including a permanent discontinuation, switch, or substitution.

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Ages Eligible for Study:

16 Years and older (Child, Adult, Senior)

Sexes Eligible for Study:

All

Accepts Healthy Volunteers:

No

Criteria

Inclusion Criteria:

HIV-infected. A resistance assay must be obtained if the participant has evidence of recent infection. More information on this criterion can be found in the protocol.

Antiretroviral naive, defined as 7 days or less of ARV treatment at any time prior to study entry. Participants who have received ARVs as part of postexposure prophylaxis or who have received an investigational drug that was not an NRTI, NNRTI, or PI are eligible for this study.